Firing mechanism for explosively actuated tool

ABSTRACT

A breech block is mounted behind the breech in the frame of an explosively actuated tool and is movable transversely of the frame to an inoperative position exposing the rear end of the cartridge-receiving bore through the breech. A firing pin is supported by the block in line with the bore. Carried by the breech block for movement transversely thereof is a springpressed detent that normally projects into a hole in the frame beside the block to hold the block with its firing pin in operative position. The frame is provided with a second hole for receiving the detent when the block has been moved to its inoperative position. Manually operable means are mounted on the frame for pushing the detent out of either of the frame holes to permit it to be moved with the block to the other hole.

Unite tates atet [151 3,665,802 Temple 1 y 30, 1972 [s41 FIRINGMECHANISM FOR 2,132,148 10/1938 Davis ..s9 24 EXPLOSIVELY ACTUATED TOOLP E s lw E I nmary xammeramue ng e [72] Inventor: Robert Temple,Pittsburgh, Pa. A0mey B1-own, Murray, Hick & peckham [73] Assignee: MineSafety Appliances Company ABSTRACT l 0 [22] Filed Apr 97 A breech blockis mounted behind the breech in the frame of [21] Appl. No.: 25,643 anexplosively actuated tool and is movable transversely of the frame to aninoperative position exposing the rear end of the cartridge-receivingbore through the breech. A firing pin is [52] U.S.Cl. ..89/l B, 42/] R,supported y the block in line with the bore Carried y the 51 I F 41d ")2breech block for movement transversely thereof is a springd I, 42/1pressed detent that normally projects into a hole in the frame 1 e o42/69' 2 beside the block to hold the block with itsfiring pin inoperative position. The frame is provided with a second hole forreceiving the detent when the block has been moved to its in- [56]References cued operative position. Manually operable means are mountedon UNITED STATES PATENTS the frame for pushing the detent out of eitherof the frame I1 892 R l 89/24 holes to permit it to be moved with theblock to the other hole. 480,627 8 oste 533,860 2/1895 Benet ..89/24 5Claims, 4 Drawing Figures 4.2 30 2? so I as f Patented May 30 1972 2Sheecs-Sheet l Patented May 30-, 1972 2 Sheets-Sheet z VEMHHIIIJ.

-1NVENTOR. 05597 TZMPLk big I Eh/EYS.

FIRING MECHANISM FOR EXPLOSIVELY ACTUATED TOOL Many explosively actuatedtools, such as cable cutters, have to be loaded and unloaded from thefront end. This not only is a time consuming process, but it can bedangerous because of the possibility of accidental discharge of thecartridge.

It is among the objects of this invention to provide such a tool whichcan be loaded and unloaded from its rear end, which is provided with afiring pin that can be quickly moved laterally from operative toinoperative position, and which is simple in construction and operation.

' The preferred embodiment of the invention is illustrated in theaccompanying drawings, in which FIG. I is a front view of the tool;

FIG. 2 is a side view shown partly in longitudinal section;

FIG. 3 is a cross section taken on the line 3-3 of FIG. 2; and

FIG. 4 is a view like FIG. 3, but with the firing pin in its inoperativeposition.

Referring to FIGS. 1 to 3 of the drawings, the metal frame 1 of the toolmay be substantially rectangular in cross section and is provided with apassage extending through it from end to end. The major portion of thispassage forms a barrel 2 for a projectile and has an anvil 3 screwedinto its front end. Directly behind the anvil the opposite sides of theframe are cut away and the front of the frame is provided with a slot 4that opens into the cable-receiving recess thus formed. To guide a cable6 into the recess, the front of the frame is provided with an inclinedguide finger 7. The rear end of the barrel forms the breech 8 of thetool, and the central bore 9 through the breech receives an explosivecartridge 10 that extends into a socket II in the rear end of a piston12 that is slidably mounted in the barrel. The front end of the pistonis tapered to form a cutting chisel 13. This piston-chisel is theprojectile of the tool. It nornially is held in position by a shearscrew I4 projecting into the side of the piston from a hole in the frontof the frame.

Directly behind the breech the frame is provided with a cylindricalopening 16 extending transversely through it from front to back.Slidably mounted in this opening is a breech block 17 that has a passage18 through it aligned with the bore in the breech. Slidably mounted inthe reduced front end of this passage is a firing pin 19. The rear endof this pin is pro vided with a head that is pivotally connected to theinner end of a lever 20 that extends outwardly though a notch 21 in theblock and into a bore 22 through a portion of the breech block thatprojects from the back of the frame. The lever normally is locked by aremovable safety pin 23. When, after this pin and another safety pin 24have been removed, the outer end of the lever is struck by aspring-pressed hammer 25 carried by the tool in the usual way, thefiring pin is driven forward against the cartridge to detonate it.

The breech block is held in its operative position just described bymeans of a pin 27 slidably mounted in a transverse passage 28 in thefront or inner end of the block. The pin is urged outwardly by a coilspring 29, and its outer end projects into a hole 30 in the side of theframe beside the breech block.

It is a feature of this invention that the breech block can be moved outof the way to permit the tool to be loaded or unloaded from the back. Inorder to do this the locking pin 27 has to be removed from the framehole so that the block can be pulled rearwardly part way out of theframe to expose the rear end of the cartridge or breech bore 9, as shownin FIG. 4. In its outer or inoperative position the locking pin snapsinto another hole 32 in the side of the frame to lock the breech blockin that position. A cartridge then can be inserted or removed throughthe open front end of passage 16 or, if desired, through a passage 33(FIG. 2) in the rear end of the frame after the handle 34, which may bea pole, is unscrewed from the frame.

In order to unlock the breech block so that it can be moved lengthwiseof frame opening 16, a stiff metal strip 36 is attached to the framebetween the two holes 30 and 32 by means of a screw 37. The screwextends though an enlarged opening in the strip, and the head of thescrew is spaced from the frame a distance greater than the thickness ofthe strip. The strip is bent so that it can rock against the frame.Thus, when the breech block is in its normal or operative position shownin FIG. 3, the strip extends across the rear hole 32 in engagement withthe frame, but immediately in front of the screw the strip is bentoutwardly away from the frame so that it is inclined away from the otherhole. Secured to the strip in line with the twoholes are studs 38 and 39that are small enough to enter the holes. While the breech block is inoperative position, the rear stud 39 extends into hole 32 but most ofthe other stud is outside of the other hole because the inner end ofthat stud is engaged by locking pin 27.

When the upper end of strip 36 is pressed toward the frame, it causesthe strip to rock and stud 38 to push the locking pin inwardly out ofthe front frame hole. Simultaneously, the strip pulls the other stud 39out of hole 32. The outer end of the breech block then can be grasped topull the block rearwardly in opening 16, which will cause the end of thelocking pin to slide along the inside of the frame until it can snapinto the rear hole to lock the block in its outer or inoperativeposition shown in FIG. 3. To reverse the block movement, the rear end ofstrip 36 is pressed toward the frame to push the locking pin out of hole32 so that the block can be pushed forward. The inner surface of theframe is provided with a groove 41 extending between the two frame holesfor receiving the outer end of the locking pin. This permits the studsto push the pin completely out of the frame holes without the studsentering breech block passage 28 and keeping it from being shifted. Theprojection of the pin into the groove also prevents the breech blockfrom turning out of position while it is being moved back and forth whenthere is no cartridge head engaging the adjoining flattened area of theblock. It also avoids any likelihood of the block being pulled entirelyout of the frame.

According to the provisions of the patent statutes, I have explained theprinciple of my invention and have illustrated and described what I nowconsider to represent its best embodiment. However, I desire to have itunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically illustrated anddescribed.

I claim:

I. An explosively actuated tool comprising a frame provided with abarrel having a breech with a cartridge-receiving bore therethrough, abreech block mounted in the frame behind said breech, a firing pinsupported by the block in line with said bore normally, means foractuating the pin, the block being movable transversely of the frame toan inoperative position exposing the rear end of said bore, a detentcarried by the block for movement transversely thereof, a spring urgingthe detent outwardly of the block, said frame being provided beside theblock with a hole therethrough into which said detent normally projectsto hold the block in operative position, the frame being provided with asecond hole for receiving the spring-pressed detent when the block hasbeen moved to said inoperative position, and manually operable meansmounted on the outside of the frame for pushing said detent inwardly outof either of said holes to permit it to be moved by the block to theother hole, said manually operable means including a first membernormally substantially engaging the outer end of said detent in thefirst hole and projecting from the frame, a second member extending intothe second hole, and means connected to the outer ends of said membersfor withdrawing the second member from the second hole as the firstmember is pushed into the first hole to push said detent out of thathole.

2. A tool according to claim 1, in which said first and second membersare studs and said connecting means is a stiff member movably connectedto the frame.

3. A tool according to claim 1, in which said detent is a longitudinallymovable pin slidably mounted in the breech block and said frame isprovided with a groove connecting the inner ends of said holes andreceiving the outer end of said pin while it is moving from one of theholes to the other.

wardly of the other hole to push said detent out of that hole.

5. A tool according to claim 2, in which said stud connecting stiffmember has a central portion rockable on the frame,

the tool including means connecting said central portion to the frame.

1. An explosively actuated tool comprising a frame provided with abarrel having a breech with a cartridge-receiving bore therethrough, abreech block mounted in the frame behind said breech, a firing pinsupported by the block in line with said bore normally, means foractuating the pin, the block being movable transversely of the frame toan inoperative position exposing the rear end of said bore, a detentcarried by the block for movement transversely thereof, a spring urgingthe detent outwardly of the block, said frame being provided beside theblock with a hole therethrough into which said detent normally projectsto hold the block in operative position, the frame being provided with asecond hole for receiving the spring-pressed detent when the block hasbeen moved to said inoperative position, and manually operable meansmounted on the outside of the frame for pushing said detent inwardly outof either of said holes to permit it to be moved by the block to theother hole, said manually operable means including a first membernormally substantially engaging the outer end of said detent in thefirst hole and projecting from the frame, a second member extending intothe second hole, and means connected to the outer ends of said membersfor withdrawing the second member from the second hole as the firstmember is pushed into the first hole to push said detent out of thathole.
 2. A tool according to claim 1, in which said first and secondmembers are studs and said connecting means is a stiff member movablyconnected to the frame.
 3. A tool according to claim 1, in which saiddetent is a longitudinally movable pin slidably mounted in the breechblock and said frame is provided with a groove connecting the inner endsof said holes and receiving the outer end of said pin while it is movingfrom one of the holes to the other.
 4. A tool according to claim 2, inwhich said stud connecting stiff means is a bowed metal strip with thestuds fastened to its opposite ends and provided with a central opening,the tool including a fastening member mounted in said frame andextending loosely through said strip opening to permit the strip to berocked, whereby to swing one of the studs outwardly of a frame hole andto simultaneously swing the other stud inwardly of the other hole topush said detent out of that hole.
 5. A tool according to claim 2, inwhich said stud connecting stiff member has a central portion rockableon the frame, the tool including means connecting said central portionto the frame.